History Theatre’s Ron Peluso took a big risk in adapting the diary of Coco Irvine for the stage. First, narratives of the interior voice (such as a diary) tend to go flat when taken out of our imaginations and reduced to stage characters. Second, Peluso was putting “Coco’s Diary” almost entirely on the shoulders of a 13-year-old actor.

With great risk comes great reward, and the History Theatre’s production that opened Saturday night has a dazzling charm. Young Coco’s vocabulary and intelligence retain all their cheeky humor and insight in Kacie Riddle’s portrayal. We leave the theater wishing that we could travel back in time and get to know this young girl who lived among St. Paul’s high society on Summit Avenue.

Clotilde (Coco) Irvine was 12 in 1926 when she received an empty diary from her parents for Christmas. On Jan. 1, 1927, she began to record her thoughts and experiences. Peluso and writer Bob Beverage smartly lift Coco’s words verbatim and dress up the show with musical selections from the era. They frame that action with scenes of a grown-up Coco and her brother, Tom, visiting their childhood home in 1965, the year it was given to the state of Minnesota as a governor’s residence.

The result is more a salon than a play, but labels don’t matter. Riddle, who alternates in the role as young Coco with Anna Evans, gave an extraordinary performance Saturday night. Riddle, whose stage credits befit someone much older, was precocious without being precious and every story seemed a fresh discovery for her. So we hear the enthusiasm and 13-year-old horror in her voice when Coco tells of being caught driving her sister’s car, sneaking out of the house late at night to dance with her brother and attempting to heist school silverware. Riddle’s phrasing and spunk are impeccable. She wins our confidence right away.

Jake Endres plays a number of roles, including Tom Irvine and their father, Horace. Andrea Wollenberg portrays the adult Coco, her mother and childhood friends. Endres and Wollenberg both play piano and sing — a versatility that fills Rich Polonek’s scenic design with energy and animation.

If Peluso wants another go at this show sometime, a trim wouldn’t hurt. That might provide for more modulation as Coco’s diary gets into October and November.

The real star of this show, sadly, is no longer with us. Coco wrote with amazing elegance and intelligence for a girl of 13. She was smart, confident, terribly honest and constantly aware of everything around her. She consumed life eagerly with great awareness, and her observations provide an indelible picture.

“I’m smarter than most people in this family,” she observes at one point. And we believe her when she defuses the silverware situation with her parents and remarks, “It pays to know how to manage things.”

As Coco herself might have written, all this makes for a very satisfactory evening.